Needle shield with specific roughness

ABSTRACT

The present invention relates to a shield ( 10 ) for the distal extremity of an administration device ( 3 ) comprising a hub ( 2 ) on which said shield ( 10 ) is to be removably engaged, said shield ( 10 ) having a wall ( 13 ) the internal face ( 14 ) of which defining an interior cavity ( 15 ) for receiving the extremity of the administration device ( 3 ), at least a portion ( 14   a ) of said internal face ( 14 ) being intended to be in contact with said hub ( 2 ) when said shield ( 10 ) is engaged on the extremity of said administration device ( 3 ), whereby said portion ( 14   a ) has, distributed over a major portion of said portion ( 14   a ), a surface feature ( 16, 17 ) that defines the amount of contact between said portion ( 14   a ) and said hub ( 2 ).

The present invention relates to a shield for covering the distalextremity of an administration device at least prior to use of theadministration device.

In this application, the term distal means the part furthest from theuser's hand, and the term proximal means the part closest to the user'shand. Likewise, in this application, the term “distal direction” meansthe direction of administration, i.e., towards the patient, and the term“proximal direction” means direction opposite to the direction ofadministration, i.e., away from the patient.

Administration devices are commonly used in several technical fieldssuch as, for example, the medical field, to administer to a patient, forexample a medical product, either by spraying for spraying devices or byinjection for injection devices. To do so, the distal extremity of theadministration device can be provided with a staked needle or nozzle ora luer connection allowing provision of an assembly such as a nozzleassembly or a needle assembly.

In the present application, by “staked needle” one means a needle fixedon the tip of the injection device by gluing or by any other suitablemethod such as for example shrinking of the tip of the syringesurrounding the needle after heating.

In the medical field, injection devices, such as syringes provided withneedles, either staked needles or needle assemblies on luer syringes,are usually provided to the end-users with needle shields: indeed,needles must remain sterilized until use and need to be protected frompossible contamination from the environment. Moreover, in the case ofinjection devices with needle, the end user must also be protected fromaccidental needle-stick injuries. Moreover, in the case of prefilledsyringes, needle shields ensure tightness and avoid the loss of contentduring storage.

Similarly, injection device such as syringe with no needle, providedwith luer or with nozzle or with luer lock fitting, are usually providedto the end-users with a tip cap protecting the extremity of the luer orof the nozzle from possible contamination from the environment.

The present invention applies to both needle shields and tip caps. Inthis application, unless it is otherwise specified, the term “shield” isused indifferently for “needle shield” or for “tip cap”.

These shields, or at least part of these shields, are usually made of anelastic material, such as a thermoplastic elastomer, such as rubber, andare secured on the distal extremity of the administration device forinstance on assembly lines of industrial pharmaceutical companies. Inthis view, the distal extremity of the administration device usuallycomprises a hub to which the needle may be secured by gluing for exampleand upon which the shield is removably engaged by friction, for example.

One of the problems encountered with the automatic assembling of needleshields on the distal extremity of an administration device in assemblylines is that the needle shield is not always adequately put on theextremity of the administration device. In particular, it can happenthat the needle shield is not directed along the longitudinal axis ofthe administration device at the time it is fit on the extremity of saiddevice. The result is that the longitudinal axis of the needle shield isnot confounded with the longitudinal axis of the administration device,the needle shield is inclined with respect with the extremity of theadministration device. As the shield is usually made of rubber, which isquite a sticky material under normal use conditions, the shield happensto stuck on the hub of the administration device in an inappropriateposition. Furthermore, it may be difficult to remove it at the time ofuse of the administration device.

Another problem caused by the fact that the shields are badly positionedis that it becomes difficult to position them in the nests of a handlingtray, in particular with automatic means of assembly lines: this maycause breakage and emergency stop of the manufacturing lines.

Moreover, in the case where the administration device comprises a stakedneedle, the tip of the needle may penetrate the elastic material formingthe shield: this phenomenon is very problematic for the subsequent useof the needle which may be contaminated by particles coming from saidelastomeric material. Furthermore, the tip of the needle may transfixthe wall of the shield, which would cause evident tightness andsterility issues. Lastly, the needle itself can be damaged, as it can bebended due to the bad positioning of the shield. FIGS. 1 a to 1 dillustrate the problem of the prior art described hereinabove. On thesefigures is shown the step of securing a needle shield 1 of the prior arton the hub 2 of the distal extremity of an administration device such assyringe 3 according to an automatic industrial process like those takingplace in assembly lines of pharmaceutical companies for example.

On FIG. 1 a is shown the beginning of the operation of securing theneedle shield 1 on the hub 2. As appears on this figure, the needleshield 1 is made of a wall 4 defining a cavity 5. On FIG. 1 a, thecavity 5 of the needle shield 1 is approached from the needle 6 fixed atthe distal extremity of the syringe 3. As can be seen from FIG. 1 a,during the approach of the needle shield 1 toward the needle 6, thelongitudinal axis A of the needle shield 1 is not parallel to thelongitudinal axis B of the syringe 3. On FIG. 1 b is shown the step ofpositioning the needle shield 1 on the extremity of the syringe 3,thanks to vibrating means. After this step, the respective longitudinalaxis A and B of the needle shield and of the administration deviceshould be parallel, but due to the stickiness of the elastomer, theneedle shield 1 remains held in an inappropriate position, in which therespective longitudinal axis A and B of the needle shield 1 and of theadministration device 3 are not parallel. In consequence, the tip 7 ofthe needle 6 enters in contact with the elastomeric wall 4 of the needleshield 1. As shown on FIG. 1 c, a distal force, represented as arrow Fon FIG. 1 c, is then applied on the needle shield 1 in order to fit iton the extremity of the administration device. On FIG. 1 c, under theaction of the distal force exerted on the needle shield 1, therespective axis of the needle shield 1 and of the administration device3 are now parallel but this causes the needle 6 to bend. On FIG. 1 d, isshown the assembly once the distal force exerted on the needle shield 1is released. The return force of the needle 6 brings the longitudinalaxis of the needle back substantially in the direction of thelongitudinal axis of the syringe 3 but this action forces the needleshield 1 to become inclined with respect to the longitudinal axis of thesyringe 3.

As appears clearly from FIG. 1 d, the elastomeric wall 4 of the needleshield 1 is stuck against the hub 2, in an incorrect position. Such aphenomenon makes it difficult to remove the needle shield at the time ofuse of the syringe. Moreover, as is clear from FIG. 1 d, the tip 7 ofthe needle 6 has penetrated the elastomeric wall 4 of the needle shield.The tip 7 of the needle 6 may be contaminated by elastomeric particlesfrom the wall 4.

There is therefore a need for a shield for covering the extremity of anadministration device, said shield allowing a correct fitting of theshield on the hub of the extremity of the administration device,especially by industrial automatic means such as those used in assemblylines. Such a shield should also be easily removable from the hub onwhich it is secured when it is decided to use the administration device,keeping good sterility and tightness properties when said shield is inplace.

The present invention meets this need by providing a shield having aspecific internal face allowing for a better fitting of the shield onthe extremity of the administration device.

A first aspect of the invention is a shield for covering at least partof the distal extremity of an administration device, said distalextremity of said administration device comprising a hub on which saidshield is intended to be removably secured, said shield having an openproximal end, a closed distal end and a longitudinal wall extending fromsaid proximal end to said distal end, the internal face of saidlongitudinal wall defining an interior cavity for receiving at leastpart of the extremity of the administration device, at least a portionof said internal face of said longitudinal wall being intended to be incontact with said hub when said shield is secured on the extremity ofsaid administration device, characterized in that said portion has,distributed over a major portion of said portion, a surface feature thatdefines the amount of contact between said portion and said hub.

In an embodiment, said surface feature of said portion is generallylongitudinal.

The shield of the invention is easily fit on the extremity of anadministration device. In particular, it is possible to fit the shieldof the invention on the extremity of an administration device in such away that the respective longitudinal axis A and B of the shield and ofthe administration device are parallel. The shield of the invention doesnot get stuck on the hub of the administration device on which it issecured. In case the administration device comprises a needle, anadvantage of the shield of the invention is that, because the needleshield is easily and correctly fit on the administration device, saidneedle does not enter in contact with the wall of the shield.

Moreover, the shield of the invention is easily removable from theextremity of the administration device when one wants to use saidadministration device. In particular, the pull out force necessary toremove the shield from the administration device is reduced with theshield of the invention.

In the present invention, said surface feature has a mean radialroughness of more than 2 μm, preferably more than 5 μm, more preferablymore than 10 μm.

In the present application, the mean radial roughness is measuredaccording the following method: roughness measurements done intriplicate are performed by using a profiler Wyko NT 1100 (VeecoInstruments Inc. Tucson USA) on scans 370 μm×240 μm with a VSI mode(Vertical Scanning Interferometry). The calibration of the apparatus isperformed following the procedure WI 7.6-20 using measuring instrumentstraceable to the National Institute of Standards and Technology (NIST).

In an embodiment of the invention, said mean radial roughness is lessthan 100 preferably less than 50 μm, more preferably less than 30 μm.

In an embodiment of the invention, said mean radial roughness is about25 μm.

For example, said surface feature defines a contact ratio between saidportion of said internal face and said hub of less than 90% when saidshield is secured on said hub, preferably less than 80%. Preferably,said contact ratio is more than 10%, preferably more than 20%. In anembodiment of the invention, said portion of said internal face isprovided with microreliefs defining a said radial roughness.

Said microreliefs may be selected among grooves, ridges, bulges andtheir combinations.

In the case where the shield is a moulded part, such a rough surface maybe obtained by a modification of the core pin on the moulds: thismodification may be obtained by any machining technique. In anotherembodiment of the invention, the portion of said internal face of saidlongitudinal wall may have undergone a surface treatment in order torender it rough.

Preferably, the micro-reliefs of said internal face are distributedregularly or randomly along a circumference of said portion of saidinternal face. The mean radial roughness of said portion, such as themicro-reliefs mentioned above, define a contact ratio between saidportion of said internal face and said hub of less than 90% when saidshield is secured on said hub: in particular, thanks to the roughness ofsaid portion, a certain percentage, for example 10% of the surface ofsaid portion is not in contact with the hub when the shield is securedon the hub. This allows air to flow between said portion and said hub,which reduces the sticky effect of the elastomer when positioning andfitting the shield on said hub or when removing said shield.

Moreover, the roughness of the portion, such as the micro-reliefsmentioned above, may guide the shield on the hub when the shield is putin place on the hub, facilitating thereby the correct fitting of theshield on said hub.

The contact ratio between said portion of said internal face and saidhub is preferably not less than 10%, otherwise the shield may not bewell secured on the administration device and some pop off effect maytake place, for instance during the sterilization of the administrationdevice after the shield has been secured on it, where a little increaseof the internal pressure of the administration device may eject theshield from it.

In an embodiment of the invention, the value of said mean radialroughness varies from the proximal end to the distal end of saidportion.

For example, said mean radial roughness may be greater in the region ofthe proximal end of said portion than in the region of the distal end ofsaid portion.

In an embodiment of the invention, said microreliefs are under the formof a plurality of grooves that are parallel to the longitudinal axis Aof said shield.

In another embodiment of the invention, said microreliefs are under theform of a plurality of grooves that are inclined with respect to thelongitudinal axis A of said shield.

Another aspect of the invention is a method for protecting the distalextremity of an administration device, characterized in it comprises thestep of securing a shield as described above on to the distal extremityof said administration device.

Preferably, said securing step is completed on an assembly line byautomatic means.

Other advantages of the present invention will now be specified with theaid of the description which follows and of the attached drawings inwhich:

FIGS. 1 a to 1 d show the steps of assembling a shield of the prior arton the extremity of an administration device,

FIG. 2 is a cross section view of a shield according to the invention,

FIG. 3 is a cross section view of a second embodiment of a shield of theinvention,

FIG. 4 is a cross section view of a third embodiment of a shield of theinvention.

On FIG. 2 is shown a shield 10 of the invention. The shield 10 isintended to cover the distal extremity of an administration device suchas a syringe 3 (partially shown on FIG. 2). Alternatively, theadministration device may be a needle assembly. The distal extremity ofthe syringe 3 is provided with a hub 2 on which is fixed a needle 6. Theshield 10 has an open proximal end 11, a closed distal end 12 and a wall13 extending from the proximal end 11 to the closed distal end 12. Theinternal face 14 of the wall 13 defines a cavity 15 for receiving partof the distal extremity of the syringe 3. A portion 14 a of the internalface 14 is intended to be in contact with the hub 2 of the distalextremity of the syringe 3 when the shield 10 is secured on the distalextremity of the syringe in order to protect said distal extremity, forexample during transport of the administration device before use.

On FIG. 2, the portion 14 a of the internal face 14 of the wall 13 has amean radial roughness of more than 2 μm and preferably less than 100 μm.Said mean radial roughness defines a contact ratio between the portion14 a and the hub 2 of less than 90% and more than 10% when the shield issecured on the hub 2. For example, said roughness is about 25 μmmeasured as described above.

Such a mean radial roughness may be obtained by modifying with machinetechnique the core pin of the moulds used for moulding the shield.

Preferably, the wall 13 is made of an elastomeric material such asrubber.

On FIG. 3 is shown another embodiment of the shield of FIG. 1 in whichthe portion 14 a of the internal face 14 of the wall 13 is provided witha plurality of grooves 16. The references designating the same elementsas in FIG. 2 have been maintained. The grooves 16 are regularlydistributed along the circumference of the portion 14 a and they areparallel to the longitudinal axis A of the shield 10. They allow the airto flow during the assembly of the shield on the hub 2. The stickysurface of the shield is smaller, so the assembly is facilitated and itis easy to have the respective longitudinal axis A and B (see FIG. 2) ofboth the shield 10 and the administration device 3 to remain confounded.The shield 10 of the invention is therefore perfectly and correctlysecured on the extremity of the administration device 3. Because of thegrooves created by the specific roughness of the portion 14 a of theinternal face 14 of the wall 13, it is then easier to remove the shield10 from the extremity of the administration device 3 at the time of useof the administration device 3.

On FIG. 4 is shown another embodiment of the shield 10 of the inventionin which the portion 14 a is provided with a plurality of inclinedgrooves 17. The grooves 17 are randomly distributed on the surface ofsaid portion 14 a. The grooves 17 cover at least 10% of the surface ofthe portion 14 a. The references designating the same elements as inFIGS. 2 and 3 have been maintained. The grooves 17 are inclined withrespect to the longitudinal axis A of the shield 10.

According to the process of the invention, it is possible to assemblethe shield 10 of the invention on the extremity of an administrationdevice in a very simple and efficient way. Because of the specificnature of the portion 14 a of the internal face 14 of the wall of theshield of the invention, the shield 10 is guided in the direction of thelongitudinal axis of the administration device. In particular, when theportion 14 a is provided with grooves (16; 17), the fitting of theshield 10 on the hub 2 is correct and the respective longitudinal axisof the shield 10 on one hand and of the administration device 3 on theother hand remain confounded. The shield 10 of the invention is allowedto be secured on an administration device 3 with automatic means such asrobots in industrial processes using assembly lines.

The shield 10 of the invention is also easy to remove at the time of usebecause of the air flow authorized by the micro-reliefs, such asgrooves, ridges or bulges, created by the specific surface of theportion 14 a of the shield 10 intended to be in contact with the hub 2of the administration device 3 when the shield 10 is secured on saidadministration device 3.

According to a variant of the invention, the grooves may be providedonly on a limited surface of said portion 14 a, closest to the proximalend of said portion 14 a.

According to another variant of the invention, the grooves may beprovided with a variable radial roughness, for instance with a greatermean radial roughness close to the proximal end of the portion 14 a.

The invention has been described with grooves ensuring the contact ratioless than 90% between the portion 14 a and the hub 2. The invention alsoapplies to other geometries for the portion 14 a, as for example ridges,bulges, or any other geometry.

1. A shield (10) for covering at least part of the distal extremity ofan administration device (3), said distal extremity of saidadministration device (3) comprising a hub (2) on which said shield (10)is intended to be removably engaged, said shield (10) having an openproximal end (11), a closed distal end (12) and a longitudinal wall (13)extending from said proximal end (11) to said distal end (12), theinternal face (14) of said longitudinal wall (13) defining an interiorcavity (15) for receiving at least part of the extremity of theadministration device (3), at least a portion (14 a) of said internalface (14) of said longitudinal wall (13) being intended to be in contactwith said hub (2 when said shield (10) is secured on the extremity ofsaid administration device (3), characterized in that said portion (14a) has, distributed over a major portion of said portion (14 a), asurface feature (16, 17) that defines the amount of contact between saidportion (14 a) and said hub (2).
 2. A shield (10) according to claim 1,characterized in that said surface feature (16) of said portion (14 a)is generally longitudinal.
 3. A shield (10) according to claim 1,characterized in that said surface feature has a mean radial roughnessof more than 2 μm, preferably more than 5 μm, and more preferably morethan 10 μm.
 4. A shield (10) according to claim 3, characterized in thatsaid surface feature has a mean radial roughness of less than 100 μm,preferably less than 50 μM, more preferably less than 30 μm.
 5. A shield(10) according to claim 4, characterized in that said mean radialroughness is about 25 μm.
 6. A shield (10) according to claim 1,characterized in that said surface feature defines a contact ratiobetween said portion (14 a) of said internal face (14) and said hub (2)of less than 90% when said shield (10) is secured on said hub (2),preferably less than 80%.
 7. A shield (10) according to claim 6,characterized in that said contact ratio is more than 10%, preferablymore than 20%.
 8. A shield (10) according to claim 4, characterized inthat said portion (14 a) of said internal face (14) is provided withmicroreliefs (16; 17) defining said radial roughness.
 9. A shield (10)according to claim 8, characterized in that said microreliefs areselected among grooves, ridges, bulges and their combinations.
 10. Ashield (10) according to claim 9, characterized in that saidmicroreliefs are distributed regularly or randomly along a circumferenceof said portion (14 a) of said internal face (14).
 11. A shield (10)according to claim 10, characterized in that said microreliefs are underthe form of a plurality of grooves (16) that are parallel to thelongitudinal axis (A) of said shield (10).
 12. A shield (10) accordingto claim 10, characterized in that said microreliefs are under the formof a plurality of grooves (17) that are inclined with respect to thelongitudinal axis (A) of said shield (10).
 13. A shield (10) accordingto claim 3, characterized in that the value of said mean radialroughness varies from the proximal end to the distal end of said portion(14 a).
 14. A shield (10) according to claim 13, characterized in thatsaid mean radial roughness is greater in the region of the proximal endof said portion (14 a) than in the region of the distal end of saidportion (14 a). 15.-16. (canceled)